Steps to reproduce:
- Go to Administration: Localization
- Type in another language in the "Supported languages" & "Default Language" fields; for ex. use "fr"
- Create a new subwiki
The Distribution Wizard is in English. After you finish installing the UI you can notice the subwiki language is still English.
From an user's POV it makes sense that if you set your main wiki to a specific language, the subwikis will be created in the same language, even if the main wiki and the subwikis are different entities.